The Giant Polypore (Meripilus giganteus) is one of Britain's largest fungi: a great rosette of overlapping, fan-shaped brackets clustered around the base of an old tree, up to 80 cm across. Each pale brown to yellowish-brown cap is radially wrinkled and banded, paler towards the edge, and the underside is a creamy layer of tiny pores. The best test is to press it, because every part slowly bruises black.
It grows on the roots and buttresses of standing broadleaf trees and stumps, especially beech, from July into November. It causes root rot, so a big flush at the foot of a park tree is a warning sign for tree surgeons.
Hen of the Woods (Grifola frondosa) has smaller, thinner grey-brown caps and does not blacken, and Chicken of the Woods (Laetiporus sulphureus) is bright yellow and orange. Young Giant Polypores are sometimes eaten, but they have caused stomach upsets, so they are best left alone.
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Distribution
Widespread and common
Habitat
On root buttresses of standing trees or stumps especially Fagus but also other broadleaved trees and rarely conifers
Etymology
Meripilus is from the Greek meris, 'part', and pilos, 'cap', after the many caps that make up each clump. giganteus is Latin for 'gigantic'.
Associates
Fagus
Fruiting Body
Large overlapping, semi-circular brackets 20-80 cm across, forming a rosette. The yellowish-brown to pale pinkish-brown surface is radially wrinkled, with concentric zones getting paler towards the margin. All parts bruise blackish.
| Cycle | annual |
|---|---|
| Colour | |
| Shape | Overlapping brackets, Semi-circular |
| Surface | Rugose |
| Width | 20 - 80 cm |
| Bruising |
Pores
The pores are tiny and cream to white, 3-5 per mm. They bruise dark brown to blackish when handled, like the rest of the fruiting body.
| Colour | |
|---|---|
| Size | small |
Tubes
The tubes are white and up to 1cm deep, forming a fairly thin layer beneath the pore surface. They darken to blackish when bruised, like the pores.
| Colour |
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Flesh
White and fibrous, soft when young; bruises black.
| Colour | |
|---|---|
| Odour | Pleasant, mushroomy |
| Taste | Mild |
Spores
| Colour | |
|---|---|
| Type | inamyloid |
| Shape | Subglobose |
| Ornamentation | Smooth |
| Size | 5.5-6 x 4.5-5.5 μm |
Classification
- ↳ Phylum: Basidiomycota
- ↳ Subphylum: Agaricomycotina
- ↳ Class: Agaricomycetes
- ↳ Order: Polyporales
- ↳ Family: Meripilaceae
- ↳ Genus: Meripilus
Synonyms
- Boletus giganteus Pers.
- Grifola gigantea (Pers. ex Fr.) Pilat
- Grifola gigantea (Pers.) Pilát
- Meripilus giganteus (Pers. ex Fr.) P. Karst.
- Polyporus giganteus (Pers.) Fr.
- Polyporus giganteus Pers. ex Fr.
Reference Sources
T. Læssøe, J. H. Peterson (2019) Fungi of Temperate Europe Vol. 2. Princeton University Press.
G. Kibby (2020) Mushrooms and Toadstools of Britain & Europe Vol. 1. Geoffrey Kibby.
Genus Meripilus
No other species found in this genus.
